#include<stdio.h>
#include<math.h>
int main()
{
    float a,b,c,p,area;
    printf("Please enter three flating number:");
    scanf("%f %f %f",&a,&b,&c);
    p=(a+b+c)/2.0;
    area=sqrt(p*(p-a)*(p-b)*(p-c));
    if((a+b>c&&a+c>b&&b+c>a)==1)
    printf("\narea=%f",area);
    else
    printf("\nfalse");
    return 0;
}